Adults: adult mosquitos are slender true flies, usually less than 1 cm long. They have long thin legs and wings. Some other true flies look like mosquitos, but only mosquitos have the long thin mouthparts called a proboscis. Adult mosquitos have long antennae, and male mosquitos antennae look very feathery. Like all true flies, mosquitos only have two wings. Their bodies and wings are covered with microscopic scales.
There are mosquitos all over the world, anywhere there is fresh water for their larvae. There are over 2,500 species of mosquitos in the world, and about 200 of them are found in North America.
Mosquitoes need still freshwater or slightly salty water for their larvae to grow, but different species have evolved to use all different kinds of water. Some grow in ponds, some in puddles, some in tree holes, some in swamps, some in salmarshes. They are most common and diverse in humid habitats but some can even be found in the arctic tundra, active during the brief summer.
Mosquitos hatch from eggs, and they start out as swimming larva. They feed and grow, then transform into a pupa. The pupa is also aquatic. The pupa doesn't grow, it's a resting stage while the mosquito transform into the adult stage. The adult is the flying stage that has legs and wings and can bite.
Most mosquitos only live for a year or so, and spend most of their lives as aquatic larvae. The adults usually only survive for a few weeks, but in some species the adults survive the winter, and the larval stage is short.
Some mosquitos are active during daylight, some at night. They don't have territories, but may stay near a body of water where they can lay eggs. They are solitary animals, and come together only to mate. However, you may sometimes see clouds of thousands or millions of mosquitos. This is because they produce many offspring and need certain kinds of habitats. Because so many mosquitos are in the same area, they appear as clouds.
Mosquitos find each other by scent and by the sound of their wing vibrations when they fly. When looking for animals to bite, they can also sense heat, moisture in the air, and the breath of animals.
Mosquitoes only feed when they are larvae and adults. Adults drink nectar from flowers for energy. Only the females bite vertebrates, such as mammals, birds, reptiles, and amphibians and feed on blood. Some species specialize in certain groups, like birds or frogs, and others will bite whatever vertebrate they can find.
The larvae of most mosquito species filter algae and bits of dead plants and animals from the water. A few species are predators on other aquatic insects, including other mosquito larvae.
The aquatic stages of mosquitoes float without moving as much as the can, trying to look like bits of debris. They will wriggle and swim away from danger if they have to. Adults can fly quickly and try to dodge away from danger as best they can. They often try to bite at night or dusk so they are hard to see. Scientists think this may be to avoid overheating, not to avoid predators.
Mosquitos play a big role in the ecosystem because they carry diseases. Many disease-causing organisms catch rides on mosquitos, going from host to host. Mosquitos have a smaller role as pollinators of flower.
World-wide, mosquitos probably cause more harm to humans than any other group of insects, because they carry so many deadly diseases. They carry diseases of humans and diseases of domesticated animals like dogs, cats, horses, and cattle.
Mosquitos help pollinate some flowers. They are important food for lots of other animals too.
No mosquitos are considered endangered. Many governments and research groups are trying to find ways to reduce the populations of mosquitos.
When mosquitos bite, they inject some chemicals that help keep the blood from clotting. The bite itches because our bodies are reacting to these chemicals.